1. Field of the Invention
This invention relates to an inverted microscope for use in observing a specimen that allows the operator to confirm the settings of the microscope from a normal viewing position, and a method for using the same.
2. Description of Related Art
As shown in FIG. 5, a conventional inverted microscope 30 has a main body 31, to which are attached a stage 32, a nosepiece 33 located below the stage 32, an objective lens 34 attached to the nosepiece 33, an eyepiece 35 located diagonally above the stage 32, and an illumination system 36 located over the stage 32. A sample container 21 for observation is placeable on the stage 32.
As shown in FIG. 6 for this conventional inverted microscope 30, the stage 32 has an opening 32a, which is used to confirm the type of objective lens 34 being used under the stage 32, and to confirm adjustments made to the operating state of the objective lens 34 using a correction ring on the objective lens 34. The opening 32a is a hole having a diameter between 100 mm and 110 mm, and is larger around than the objective lens 34. A transparent annular disk 32c, which is made of a glass or a resin, is fitted into the opening 32a and allows an observer to view and confirm the conditions around the objective lens 34.
As shown in FIG. 7 for this conventional inverted microscope 30, a sample container 21, such as a petri dish having an internal diameter of approximately between 35 mm and 100 mm, or a ninety-six-holes plate, are both widely used. However, when the sample container 21 is placed on the stage 32, the sample container 21 often blocks the field of view through annular disk 32c, and thus the conditions around the objective lens 34 cannot be confirmed by the observer from near the eye piece 35, diagonally above. As a result, an observer is forced to take an awkward position to confirm the conditions around the objective lens 34, and he/she cannot stay in the normal position for observation using the microscope 30.
One solution to this problem is to manufacture the stage 32 from glass materials. However, this solution causes other problems, such as an increased cost for machining since glass materials are heavier and more difficult to work with than when the stage 32 is manufactured from aluminum using die-casting or resin moulding. In addition, when the observer is performing a physiological experiment, the observer needs a tap in order to affix a micro-manipulator (not shown) on the stage 32. However, observers have found it difficult to bore the tap-hole on the stage 32 when it is made of glass. An alternative solution is to use a special tool, which is otherwise useless and wasted, to grasp the stage 32 without a tap in order to affix the micro-manipulator, thus increasing the operating cost of the inverted microscope 30. Therefore, while it is possible to manufacture the whole of stage 32 from a glass material, this causes both manufacturing and user problems as discussed above.